Intermittent incubation and thermal impedance

eggs

Many birds incubate their eggs intermittently, that is they alternate between periods of sitting on their eggs interspersed with periods where the eggs is left open to the air. Maintenance of egg temperature depends upon the schedule, that is how long the bird sits on the egg and how long it spends away from the nest.

The transfers of heat between the egg and parent are therefore transient-state, and cost to the parent depends not upon the conductance of the egg to heat transfer, but its impedance, a kind of non-steady-state resisteance. These are unfamiliar concepts to most, and quite a bit of my postdoctoral work was working out the implications of this for egg properties and our understanding of heat flow.

ed publications

Turner, J. S. (1994). Time and energy in the intermittent incubation of birds' eggs. Israel Journal of Zoology 40: 519-540.

Turner, J. S. (1994). Transient thermal properties of contact-incubated chicken eggs. Physiological Zoology 67(6): 1426-1447.

Turner, J. S. (1994). Thermal impedance of a contact-incubated bird's egg. Journal of Thermal Biology 19: 237-243.

Turner, J. S. (1997). On the thermal capacity of a bird's egg warmed by a brood patch. Physiological Zoology 70: 470-480.

Incubation links

Main

Scaling

Contact warming

Impedance